Researchers have claimed that a molecule critical to stem cell function plays a major role in determining human hair color. The study describes for the first time the molecular basis for one of our most noticeable traits. It also outlines how tiny DNA changes can reverberate through our genome in ways that may affect evolution migration and even human history. David Kingsley PhD professor of developmental biology said they've been trying to track down the genetic and molecular basis of naturally occurring traits - such as hair and skin pigmentation - in fish and humans to get insight into